Hybrid origin of Japanese mice "Mus musculus molossinus": evidence from restriction analysis of mitochondrial DNA

The Japanese mouse, Mus musculus molossinus, has long been considered an independent subspecies of the house mouse. A survey of restriction- site haplotypes of mitochondrial DNA (mtDNA) showed that Japanese mice have two main maternal lineages. The most common haplotype is closely related to the mtDNA of the European subspecies M. m. musculus. The other common haplotype and two minor ones are closely related to each other and to the mtDNA of an Asiatic subspecies, M. m. castaneus. Two other rare variants are probably the result of recent contamination by European M. m. domesticus. The musculus type of mtDNA is found in the southern two-thirds of Japan, whereas the common castaneus type is found in the northern third and the minor variants are found sporadically throughout Japan. The castaneus mtDNA lineage had a few minor variants, whereas the musculus lineage was completely monomorphic. By contrast, the native population of M. m. castaneus and the Chinese and Korean musculus populations were highly polymorphic. These results suggest that M. m. molossinus is a hybrid between ancestral colonies, possibly very small, of M. m. musculus and M. m. castaneus, rather than an independent subspecies.      

Interferon effects on microfilament organization cellular fibronectin distribution, and cell motility in human fibroblasts

We have shown previously (Pfeffer et al., 1979, Exp. Cell Res. 121:111-120) that treatment of human fibroblasts, planted at a density of 2x10(3) cells/cm(2), with purified human fibroblasts interferon (640 U/ml) for 3 d at 37 degrees C decreases the overall rate of cell proliferation to 35-40 percent of the control value. In the present experiments we have characterized the phenotype of interferon-inhibited fibroblasts. The mean volume of trypsinized, interferon-treated cells was increased 31 percent abover that of control cells. The interferon-treated population was much more heterogeneous than the control population with respect to volume, and there was a considerable overlap in the volume distributions of the two populations. The cell surface area was, on the average, increased 65 percent after interferon treatment. More than 80 percent of the treated cells had enlarged nuclei, many of which were lobed, and the fraction of binucleated cells was increased fivefold. After interferon treatment, over 40 percent of the cells showed large actin-containing fibers in the form of multiple parallel arrays. Fewer than 5 percent of the control cells contained such large actin fibers. The number of actin fibers of all sizes was tripled in the treated fibroblasts on a per cell basis and, calculated per unit surface area of the cells, the number was increased 82 percent. In contrast, 10-nm filaments and microtubules did not appear to be increased in number per unit surface area of the cells. The increases per cell in the abundance of these structures were directly related to increased cell size. After interferon treatment, fibronection was distributed in arrays of long filaments covering most portions of the cell surface. Interferon treatment markedly decreased the rate of cell locomotion as well as membrane ruffling and saltatory movements of intracellular granules.     

A simple hydroponic hardening system and the effect of nitrogen source on the acclimation of <Emphasis Type="Italic">in vitro</Emphasis> cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz)

Plant tissue culture technology is being widely used for large-scale, rapid, clonal multiplication and genetic transformation in cassava. The main limitation of this technology is the period of acclimation of the fragile in vitro plants after they have been multiplied or regenerated. Most losses of in vitro plants occur when the plantlets are moved directly from the test tubes to the ex vitro conditions. Our aim was to design a simple, rapid, low-maintenance hydroponic system to improve survival rate of transplanting to the ex vitro conditions through the rapid acclimation process of in vitro plants. In this paper, we have developed a simple hydroponic system to accelerate the cassava acclimation and multiplication process. This system considerably increased the survival percentage of in vitro and/or transgenic lines and reduces the time requirement for multiplication by hydroponic acclimation. In order to assess the effectiveness of the acclimation of seedlings on their establishment, we analyzed plant growth and field survival rate with response to different nitrogen (N) sources using different cassava accessions. Nitrogen sources of NO₃ ^? and NH₄NO₃ increased plant growth and root length compared to NH₄ ⁺ alone, or water treatments. The greenhouse and field survivability of N-hardened plants, including transgenic lines, were significantly different in growth and development. We present a simple NO₃ ^? hydroponic acclimation system that can be quickly and cheaply constructed and used by the cassava community around the world. The efficiency of our proposed N hydroponic acclimation system is validated in the transgenic development pipeline which will enhance the cassava molecular breeding.     

Phase II protocol for the evaluation of new treatments in patients with advanced gastric carcinoma: results of ECOG 5282

The study was a Phase II randomized study to evaluate the efficacy of new agents for the treatment of advanced gastric carcinoma. Patients were randomized to receive single agent chemotherapy with mitoxantrone, etoposide, aclacinomycin-A or spirogermanium. The patients were stratified by prior use of chemotherapy, prior doxorubicin use and ECOG performance status. Patients with a history of cardiac disease or prior doxorubicin exceeding a dose of 400 mg/m² were restrictively randomized to sopirogermanium or etoposide only. One hundred and fourteen patients were registered for the study. Among 98 evaluable patients there were only two partial responses (both in the etoposide arm), and one complete response in the mitoxantrone arm. The median survival on the study was 3.3 months. One hundred and six patients were analyzable for toxicity. There were four treatment-related deaths and four life-threatening toxicities. Because of low response rates and relatively high toxicities the studied compounds were not deemed worth further investigation for advanced gastric cancer.     

Spatial Behavior Comparison of Bactericera cockerelli Sulc. (Hemiptera: Triozidae) in Mexico

During the last five?years, Bactericera cockerelli Sulc. has caused significant economic losses in potato production in Mexico, due to the purple top and zebra chip diseases, since it acts as the vector of Candidatus Liberibacter psyllaurous. Despite its importance as a vector of serious potato diseases, the knowledge of its spatial distribution behavior, which could improve the efficiency of control measures, is entirely lacking. The main objective of this work was to compare the spatial distribution of the immature and adult stages of B. cockerelli obtained in a potato field by means of transect and quadrant sampling techniques and of geostatistics tools that allow the visualization of its spatial distribution in the field. Transect and quadrant samplings showed that the immature stages (eggs and nymphs) of B. cockerelli present a clustered distribution. The validation of the achieved semivariograms in the three dates of sampling corroborated the aggregated distribution of immatures and adults of the insect. The maps obtained in the sampling by using the quadrant or the transect approaches reflect the aggregated structure of the insect populations which did not infest 100% of the plot area. This allowed us to identify infested and free areas, what will aid in decisions for selecting alternatives of control.     

黑龙江和图们江流域菱属(Trapa L.)植物分布格局及形态多样性

菱属(Trapa L.)的系统分类一直存在较大分歧,至今还没有一个比较公认的分类系统。黑龙江和图们江流域是菱属物种多样性的重要分布区之一,为了揭示该流域菱属植物的地理分布格局和形态多样性,我们进行了大量实地调查和研究。结果显示,从该地区28个湖中共采集到菱属11个种及8个种内变异类型,表明它们具有丰富的形态多样性;结合查阅菱属354份标本资料,共获得92个分布地点数据;采集到的11个物种的地理分布格局呈不均衡性,其中细果野菱(Trapa maximowiczii Korsch.)分布最广,野菱(Trapa incisa Siebold et Zucc.)、兴凯菱(Trapa khankensis Pshennikova)和科热夫尼科夫菱(Trapa kozhevnikovirum Pshennikova)为狭域分布种;东部乌苏里江和图们江流域是菱属物种多样性的分布中心,可能是第四纪冰期避难所;菱属植物多数种间形态特性相对稳定,东北菱(Trapa manshurica Fler.)、耳菱(Trapa potaninii V.Vassil)、丘角菱(Trapa japonica Fler.)、西伯利亚菱(Trapa sibirica Fler.)和细果野菱共有8个种内形态变异类型;种群内多数分类性状稳定,种群间形态变异较明显;菱属植物分布格局不均衡和种内形态变异的形成可能与基因流的扩散限制有关。本研究结果为进一步澄清菱属分类混乱问题奠定了基础,进一步结合分子标记技术研究系统演化关系将对揭示菱属的进化历史具有重要意义。